JavaFX 中的属性绑定（例题）

最新推荐文章于 2020-12-27 13:07:35 发布

转载最新推荐文章于 2020-12-27 13:07:35 发布 · 400 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/PabloZeal/p/7536634.html

文章标签：

#java

本文通过一个具体的JavaFX示例展示了如何使用绑定功能来自动调整图形界面元素的位置和大小。这些元素包括矩形和线条，它们的位置和大小会随着父容器尺寸的变化而自动更新。

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JavaFX的属性经常通过绑定来综合。这是一种表达变量间关系的机制。可以将一个目标对象和一个源对象绑定，如果源对象中的值改变了，则目标对象也将自动改变。目标对象称为绑定对象或绑定属性，源对象称为可绑定对象或可观察对象。下。下列程序是对《Java 程序语言设计》其中一道习题的实现（原答案并不完整）：

 1 import javafx.application.Application;
 2 import javafx.scene.Scene;
 3 import javafx.scene.layout.Pane;
 4 import javafx.scene.paint.Color;
 5 import javafx.scene.shape.Line;
 6 import javafx.scene.shape.Rectangle;
 7 import javafx.stage.Stage;
 8 
 9 public class java1414 extends Application {
10     @Override // Override the start method in the Application class
11     public void start(Stage primaryStage) {
12         Pane pane = new Pane();
13         double paneWidth = 200;
14         double paneHeight = 200;
15 
16         // Draw the front rectangle
17         Rectangle r1 = new Rectangle();
18         r1.xProperty().bind(pane.widthProperty().multiply(0.05));
19         r1.yProperty().bind(pane.heightProperty().multiply(0.30));
20         r1.widthProperty().bind(pane.widthProperty().multiply(0.75));
21         r1.heightProperty().bind(pane.heightProperty().multiply(0.60));
22         r1.setFill(new Color(1, 1, 1, 0));
23         r1.setStroke(Color.BLACK);
24 
25         // Draw the back rectangle
26         Rectangle r2 = new Rectangle();
27         r2.xProperty().bind(pane.widthProperty().multiply(0.15));
28         r2.yProperty().bind(pane.heightProperty().multiply(0.06));
29         r2.widthProperty().bind(pane.widthProperty().multiply(0.75));
30         r2.heightProperty().bind(pane.heightProperty().multiply(0.60));
31         r2.setFill(new Color(1, 1, 1, 0));
32         r2.setStroke(Color.BLACK);
33 
34         // Connect the corners
35         Line line1 = new Line();
36         line1.startXProperty().bind(pane.widthProperty().multiply(0.05));
37         line1.startYProperty().bind(pane.heightProperty().multiply(0.30));
38         line1.endXProperty().bind(pane.widthProperty().multiply(0.15));
39         line1.endYProperty().bind(pane.heightProperty().multiply(0.06));
40         Line line2 = new Line();
41         line2.startXProperty().bind(pane.widthProperty().multiply(0.05));
42         line2.startYProperty().bind(pane.heightProperty().multiply(0.90));
43         line2.endXProperty().bind(pane.widthProperty().multiply(0.15));
44         line2.endYProperty().bind(pane.heightProperty().multiply(0.66));
45         Line line3 = new Line();
46         line3.startXProperty().bind(pane.widthProperty().multiply(0.80));
47         line3.startYProperty().bind(pane.heightProperty().multiply(0.30));
48         line3.endXProperty().bind(pane.widthProperty().multiply(0.90));
49         line3.endYProperty().bind(pane.heightProperty().multiply(0.06));
50         Line line4 = new Line();
51         line4.startXProperty().bind(pane.widthProperty().multiply(0.80));
52         line4.startYProperty().bind(pane.heightProperty().multiply(0.90));
53         line4.endXProperty().bind(pane.widthProperty().multiply(0.90));
54         line4.endYProperty().bind(pane.heightProperty().multiply(0.66));
55 
56         pane.getChildren().addAll(r1, r2, line1, line2, line3, line4);
57 
58         // Create a scene and place it in the stage
59         Scene scene = new Scene(pane, paneWidth, paneHeight);
60         primaryStage.setTitle("Exercise14_14"); // Set the stage title
61         primaryStage.setScene(scene); // Place the scene in the stage
62         primaryStage.show(); // Display the stage
63     }
64 }